1. Field of the Invention
The present invention relates to semiconductor memory devices, and more particularly, to a semiconductor memory device having a sense amp over-driving structure and method of over-driving a sense amplifier thereof.
2. Discussion of Related Art
As a driving voltage of semiconductor memory devices is gradually lowered, the processing speed thereof requires the high speed and several technical solutions for satisfying the requirement have been proposed. One of them is a sense amp over-driving method in which a sense amplifier is driving with a driving power being divided into two. However, the sense amp over-driving method has a drawback in that current of a memory device is excessively consumed due to excessive over-driving.
Of the existing over-driving methods, there is a blind method. In the blind method, when a restore line RTO connected to a PMOS transistor of a sense amplifier (not shown) and a restore line /S connected to a NMOS transistor of the sense amplifier are enabled, an external power supply voltage (VDD) and a cell power supply voltage (Vcore) are shorted for a predetermined pulse period to prevent the cell power supply voltage (Vcore) from lowering. The blind method, however, has a drawback in that excessive current is consumed since current is supplied to the corresponding whole bank.